The present disclosure relates to well bore operations, and, more particularly, to methods and apparatuses for releasing a chemical into a well bore upon command.
Settable compositions such as cement slurries may be used in primary cementing operations in which pipe strings, such as casing and liners, are cemented in well bores. In performing primary cementing, a cement may be pumped, for example, through the casing into an annulus between the walls of a well bore and the casing disposed therein. The cement may be pumped into the annulus until it reaches a predetermined height in the well bore to provide zonal isolation. The cement may cure in the annulus, thereby forming an annular sheath of hardened cement (e.g., a cement sheath) that supports and positions the pipe string in the well bore and bonds the exterior surface of the pipe string to the walls of the well bore.
In many applications, it may be desirable to have a deployment means to release one or more chemicals into the annulus between the well bore and the casing so that the chemical need not be pumped from the surface at the top of the well bore. Moreover, in the case of cementing operations, it may be desirable to not activate a cement composition in the annulus until a specific time chosen by an operator. Providing such a deployment means may entail a number of complications such as complex and expensive equipment and procedures. Therefore, it may be desirable to have methods and apparatuses for chemical deployment that are inexpensive, not complex, and require minimal modification to existing procedures such as cementing procedures.